When DC power is applied to a capacitive load, the capacitors initially draw a large amount of current before approaching a steady state value. Since the current of a capacitor is determined by the product of its capacitance and the rate of change in voltage with respect to time, the step response of input voltage will cause a large surge of current into the capacitor, referred to as inrush current. While inrush current may be limited by an equivalent series resistance of the capacitor, inrush current still can cause a considerable amount of stress on the capacitor and can cause the capacitor to fail prematurely.
Limiting inrush current is especially important for those applications that need to be turned on each time the device needs to be used, such as control systems in an automobile. An efficient inrush current limiter limits the inrush current during the startup transient but will not impact the transfer of power to the load under normal operation. This is critical for applications that need to be turned on each time the device is used, since repeated inrush currents can damage bulk capacitive loads.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.